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Sakyi PO, Broni E, Amewu RK, Miller WA, Wilson MD, Kwofie SK. Targeting Leishmania donovani sterol methyltransferase for leads using pharmacophore modeling and computational molecular mechanics studies. INFORMATICS IN MEDICINE UNLOCKED 2023. [DOI: 10.1016/j.imu.2023.101162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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Sakyi PO, Broni E, Amewu RK, Miller WA, Wilson MD, Kwofie SK. Homology Modeling, de Novo Design of Ligands, and Molecular Docking Identify Potential Inhibitors of Leishmania donovani 24-Sterol Methyltransferase. Front Cell Infect Microbiol 2022; 12:859981. [PMID: 35719359 PMCID: PMC9201040 DOI: 10.3389/fcimb.2022.859981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Accepted: 04/28/2022] [Indexed: 11/13/2022] Open
Abstract
The therapeutic challenges pertaining to leishmaniasis due to reported chemoresistance and toxicity necessitate the need to explore novel pathways to identify plausible inhibitory molecules. Leishmania donovani 24-sterol methyltransferase (LdSMT) is vital for the synthesis of ergosterols, the main constituents of Leishmania cellular membranes. So far, mammals have not been shown to possess SMT or ergosterols, making the pathway a prime candidate for drug discovery. The structural model of LdSMT was elucidated using homology modeling to identify potential novel 24-SMT inhibitors via virtual screening, scaffold hopping, and de-novo fragment-based design. Altogether, six potential novel inhibitors were identified with binding energies ranging from −7.0 to −8.4 kcal/mol with e-LEA3D using 22,26-azasterol and S1–S4 obtained from scaffold hopping via the ChEMBL, DrugBank, PubChem, ChemSpider, and ZINC15 databases. These ligands showed comparable binding energy to 22,26-azasterol (−7.6 kcal/mol), the main inhibitor of LdSMT. Moreover, all the compounds had plausible ligand efficiency-dependent lipophilicity (LELP) scores above 3. The binding mechanism identified Tyr92 to be critical for binding, and this was corroborated via molecular dynamics simulations and molecular mechanics Poisson–Boltzmann surface area (MM-PBSA) calculations. The ligand A1 was predicted to possess antileishmanial properties with a probability of activity (Pa) of 0.362 and a probability of inactivity (Pi) of 0.066, while A5 and A6 possessed dermatological properties with Pa values of 0.205 and 0.249 and Pi values of 0.162 and 0.120, respectively. Structural similarity search via DrugBank identified vabicaserin, daledalin, zanapezil, imipramine, and cefradine with antileishmanial properties suggesting that the de-novo compounds could be explored as potential antileishmanial agents.
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Affiliation(s)
- Patrick O. Sakyi
- Department of Chemistry, School of Physical and Mathematical Sciences, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
- Department of Chemical Sciences, School of Sciences, University of Energy and Natural Resources, Sunyani, Ghana
| | - Emmanuel Broni
- Department of Biomedical Engineering, School of Engineering Sciences, College of Basic & Applied Sciences, University of Ghana, Accra, Ghana
- Department of Parasitology, Noguchi Memorial Institute for Medical Research (NMIMR), College of Health Sciences (CHS), University of Ghana, Accra, Ghana
| | - Richard K. Amewu
- Department of Chemistry, School of Physical and Mathematical Sciences, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
| | - Whelton A. Miller
- Department of Medicine, Loyola University Medical Center, Maywood, IL, United States
- Department of Molecular Pharmacology and Neuroscience, Loyola University Medical Center, Maywood, IL, United States
- Department of Chemical and Biomolecular Engineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, United States
| | - Michael D. Wilson
- Department of Parasitology, Noguchi Memorial Institute for Medical Research (NMIMR), College of Health Sciences (CHS), University of Ghana, Accra, Ghana
- Department of Medicine, Loyola University Medical Center, Maywood, IL, United States
| | - Samuel Kojo Kwofie
- Department of Biomedical Engineering, School of Engineering Sciences, College of Basic & Applied Sciences, University of Ghana, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, West African Centre for Cell Biology of Infectious Pathogens, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
- *Correspondence: Samuel Kojo Kwofie,
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Cullen DR, Gallagher A, Duncan CL, Pengon J, Rattanajak R, Chaplin J, Gunosewoyo H, Kamchonwongpaisan S, Payne A, Mocerino M. Synthesis and evaluation of tetrahydroisoquinoline derivatives against Trypanosoma brucei rhodesiense. Eur J Med Chem 2021; 226:113861. [PMID: 34624822 DOI: 10.1016/j.ejmech.2021.113861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Revised: 09/16/2021] [Accepted: 09/17/2021] [Indexed: 11/24/2022]
Abstract
Human African Trypanosomiasis (HAT) is a neglected tropical disease caused by the parasitic protozoan Trypanosoma brucei (T. b.), and affects communities in sub-Saharan Africa. Previously, analogues of a tetrahydroisoquinoline scaffold were reported as having in vitro activity (IC50 = 0.25-70.5 μM) against T. b. rhodesiense. In this study the synthesis and antitrypanosomal activity of 80 compounds based around a core tetrahydroisoquinoline scaffold are reported. A detailed structure activity relationship was revealed, and five derivatives (two of which have been previously reported) with inhibition of T. b. rhodesiense growth in the sub-micromolar range were identified. Four of these (3c, 12b, 17b and 26a) were also found to have good selectivity over mammalian cells (SI > 50). Calculated logD values and preliminary ADME studies predict that these compounds are likely to have good absorption and metabolic stability, with the ability to passively permeate the blood brain barrier. This makes them excellent leads for a blood-brain barrier permeable antitrypanosomal scaffold.
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Affiliation(s)
- Danica R Cullen
- School of Molecular and Life Sciences - Curtin University, GPO Box U1987, Perth, WA, 6845, Australia
| | - Ashlee Gallagher
- School of Molecular and Life Sciences - Curtin University, GPO Box U1987, Perth, WA, 6845, Australia.
| | - Caitlin L Duncan
- School of Molecular and Life Sciences - Curtin University, GPO Box U1987, Perth, WA, 6845, Australia
| | - Jutharat Pengon
- BIOTEC Medical Molecular Biotechnology Research Group - National Science and Technology Development Agency, 113 Thailand Science Park, Phahonyothin Road, Khlong Luang, Pathum Thani, 12120, Thailand
| | - Roonglawan Rattanajak
- BIOTEC Medical Molecular Biotechnology Research Group - National Science and Technology Development Agency, 113 Thailand Science Park, Phahonyothin Road, Khlong Luang, Pathum Thani, 12120, Thailand
| | - Jason Chaplin
- Epichem Pty Ltd. Suite 5, 3 Brodie-Hall Drive Bentley, WA, 6102, Australia
| | - Hendra Gunosewoyo
- Curtin Medical School - Curtin University, GPO Box U1987, Perth, WA, 6845, Australia
| | - Sumalee Kamchonwongpaisan
- BIOTEC Medical Molecular Biotechnology Research Group - National Science and Technology Development Agency, 113 Thailand Science Park, Phahonyothin Road, Khlong Luang, Pathum Thani, 12120, Thailand
| | - Alan Payne
- School of Molecular and Life Sciences - Curtin University, GPO Box U1987, Perth, WA, 6845, Australia
| | - Mauro Mocerino
- School of Molecular and Life Sciences - Curtin University, GPO Box U1987, Perth, WA, 6845, Australia.
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Sakyi PO, Amewu RK, Devine RNOA, Bienibuor AK, Miller WA, Kwofie SK. Unravelling the myth surrounding sterol biosynthesis as plausible target for drug design against leishmaniasis. J Parasit Dis 2021; 45:1152-1171. [PMID: 34790000 PMCID: PMC8556451 DOI: 10.1007/s12639-021-01390-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 04/07/2021] [Indexed: 12/13/2022] Open
Abstract
The mortality rate of leishmaniasis is increasing at an alarming rate and is currently second to malaria amongst the other neglected tropical diseases. Unfortunately, many governments and key stakeholders are not investing enough in the development of new therapeutic interventions. The available treatment options targeting different pathways of the parasite have seen inefficiencies, drug resistance, and toxic side effects coupled with longer treatment durations. Numerous studies to understand the biochemistry of leishmaniasis and its pathogenesis have identified druggable targets including ornithine decarboxylase, trypanothione reductase, and pteridine reductase, which are relevant for the survival and growth of the parasites. Another plausible target is the sterol biosynthetic pathway; however, this has not been fully investigated. Sterol biosynthesis is essential for the survival of the Leishmania species because its inhibition could lead to the death of the parasites. This review seeks to evaluate how critical the enzymes involved in sterol biosynthetic pathway are to the survival of the leishmania parasite. The review also highlights both synthetic and natural product compounds with their IC50 values against selected enzymes. Finally, recent advancements in drug design strategies targeting the sterol biosynthesis pathway of Leishmania are discussed.
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Affiliation(s)
- Patrick O. Sakyi
- Department of Chemistry, School of Physical and Mathematical Sciences, College of Basic and Applied Sciences, University of Ghana, PMB LG 56, Legon, Accra, Ghana
- Department of Chemical Sciences, School of Sciences, University of Energy and Natural Resources, Box 214, Sunyani, Ghana
| | - Richard K. Amewu
- Department of Chemistry, School of Physical and Mathematical Sciences, College of Basic and Applied Sciences, University of Ghana, PMB LG 56, Legon, Accra, Ghana
| | - Robert N. O. A. Devine
- Department of Chemical Sciences, School of Sciences, University of Energy and Natural Resources, Box 214, Sunyani, Ghana
| | - Alfred K. Bienibuor
- Department of Chemical Sciences, School of Sciences, University of Energy and Natural Resources, Box 214, Sunyani, Ghana
| | - Whelton A. Miller
- Department of Medicine, Loyola University Medical Center, Maywood, IL 60153 USA
- Department of Molecular Pharmacology and Neuroscience, Loyola University Medical Center, Maywood, IL 60153 USA
- Department of Chemical and Biomolecular Engineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, IL 19104 USA
| | - Samuel K. Kwofie
- Department of Biomedical Engineering, School of Engineering Sciences, College of Basic & Applied Sciences, University of Ghana, PMB LG 77, Legon, Accra, Ghana
- West African Center for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
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Moreno-Herrera A, Cortez-Maya S, Bocanegra-Garcia V, Banik BK, Rivera G. Recent Advances in the Development of Broad-Spectrum Antiprotozoal Agents. Curr Med Chem 2021; 28:583-606. [PMID: 32124688 DOI: 10.2174/0929867327666200303170000] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 11/05/2019] [Accepted: 01/01/2020] [Indexed: 11/22/2022]
Abstract
Infections caused by Trypanosoma brucei, Trypanosoma cruzi, Leishmania spp., Entamoeba histolytica, Giardia lamblia, Plasmodium spp., and Trichomonas vaginalis, are part of a large list of human parasitic diseases. Together, they cause more than 500 million infections per year. These protozoa parasites affect both low- and high-income countries and their pharmacological treatments are limited. Therefore, new and more effective drugs in preclinical development could improve overall therapy for parasitic infections even when their mechanisms of action are unknown. In this review, a number of heterocyclic compounds (diamidine, guanidine, quinoline, benzimidazole, thiazole, diazanaphthalene, and their derivatives) reported as antiprotozoal agents are discussed as options for developing new pharmacological treatments for parasitic diseases.
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Affiliation(s)
- Antonio Moreno-Herrera
- Laboratorio de Biotecnologia Farmaceutica, Centro de Biotecnologia Genomica, Instituto Politecnico Nacional, Reynosa 88710, Mexico
| | - Sandra Cortez-Maya
- Instituto de Quimica, Universidad Nacional Autonoma de Mexico, Cd. Universitaria, Circuito Exterior, Coyoacan, Ciudad de Mexico 04510, Mexico
| | - Virgilio Bocanegra-Garcia
- Laboratorio de Biotecnologia Farmaceutica, Centro de Biotecnologia Genomica, Instituto Politecnico Nacional, Reynosa 88710, Mexico
| | - Bimal Krishna Banik
- Department of Mathematics and Natural Sciences, College of Sciences and Human Studies, Deanship of Research, Prince Mohammad Bin Fahd University, Al Khobar, Saudi Arabia
| | - Gildardo Rivera
- Laboratorio de Biotecnologia Farmaceutica, Centro de Biotecnologia Genomica, Instituto Politecnico Nacional, Reynosa 88710, Mexico
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Mukherjee S, Xu W, Hsu FF, Patel J, Huang J, Zhang K. Sterol methyltransferase is required for optimal mitochondrial function and virulence in Leishmania major. Mol Microbiol 2019; 111:65-81. [PMID: 30260041 PMCID: PMC6351164 DOI: 10.1111/mmi.14139] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/21/2018] [Indexed: 12/24/2022]
Abstract
Limited knowledge on the exact functions of ergostane-based sterols has hampered the application of sterol synthesis inhibitors against trypanosomatid parasites. Sterol methyltransferase (SMT) is directly involved in the synthesis of parasite-specific C24-methylated sterols, including ergosterol and 5-dehydroepisterol. While pharmacological studies hint at its potential as a drug target against trypanosomatids, direct evidence for the cellular function and essentiality of SMT is lacking. Here, we characterized the SMT knockout mutants and their complemented strains in Leishmania major, the causative agent for cutaneous leishmaniasis. Deletion of SMT alleles led to a complete loss of C24-methylated sterols, which were replaced by cholestane-based sterols. SMT-null mutants were fully viable and replicative in culture but showed increased sensitivity to sphingolipid synthesis inhibition. They were not particularly vulnerable to heat, acidic pH, nitrosative or oxidative stress, yet exhibited high mitochondrial membrane potential and increased superoxide generation indicating altered physiology of the mitochondria. Despite possessing high levels of GPI-anchored glycoconjugates, SMT-null mutants showed significantly attenuated virulence in mice. In total, our study reveals that the biosynthesis of ergostane-based sterols is crucial for the proper function of mitochondria and the proliferation of Leishmania parasites in mammals.
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Affiliation(s)
- Sumit Mukherjee
- Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409, USA
| | - Wei Xu
- Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409, USA
- Current address: Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Fong-Fu Hsu
- Mass Spectrometry Resource, Division of Endocrinology, Diabetes, Metabolism, and Lipid research, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Jigesh Patel
- Department of Physics, Texas Tech University, Lubbock, TX 79409, USA
| | - Juyang Huang
- Department of Physics, Texas Tech University, Lubbock, TX 79409, USA
| | - Kai Zhang
- Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409, USA
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Freitas HF, Pires ABL, Castilho MS. Combined Strategies to Improve the Expression of Recombinant Sterol C24-Methyltransferase from Leishmania braziliensis in E. coli. Mol Biotechnol 2018; 60:271-278. [PMID: 29488127 DOI: 10.1007/s12033-018-0069-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Among the neglected tropical diseases, leishmaniasis stands out for its worldwide distribution and diversity of symptoms. Cutaneous leishmaniasis (CL), for instance, is endemic in 18 countries, but the available drugs to fight it have high toxicity and low patient adherence. In order to overcome this, dilemma drugs that target enzymes which are absent in the human host, such as Leishmania braziliensis sterol C24-methyltransferase (SMT-C24, EC 2.1.1.41), are needed. However, medicinal chemistry efforts toward this goal have been hampered by the low yield of soluble recombinant SMT-C24 afforded by currently available expression systems. Herein, we show that a combination of molecular biology and chromatographic strategies may increase the yield of LbSMT-C24 in up to fivefold. These results lay the ground for future investigation of this enzyme as a drug target.
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Affiliation(s)
- Humberto F Freitas
- Faculdade de Farmácia, Universidade Federal da Bahia, Salvador, BA, 40170-290, Brazil.,Programa de pós-graduação em Biotecnologia, Universidade Estadual de Feira de Santana, Feira de Santanta, BA, 44036-900, Brazil
| | | | - Marcelo S Castilho
- Faculdade de Farmácia, Universidade Federal da Bahia, Salvador, BA, 40170-290, Brazil. .,Programa de pós-graduação em Biotecnologia, Universidade Estadual de Feira de Santana, Feira de Santanta, BA, 44036-900, Brazil.
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Bauerenol Acetate, the Pentacyclic Triterpenoid from Tabernaemontana longipes, is an Antitrypanosomal Agent. Molecules 2018; 23:molecules23020355. [PMID: 29419735 PMCID: PMC5911922 DOI: 10.3390/molecules23020355] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 02/02/2018] [Accepted: 02/06/2018] [Indexed: 01/11/2023] Open
Abstract
The Latin American plant Tabernaemontana longipes was studied in this work as a potential source of antiparasitic agents. The chloroform extract of T. longipes leaves was separated into several fractions, and tested for antitrypanosomal activity. One of the fractions displayed significant growth inhibitory activity against Trypanosoma brucei. The active principle in the fraction was isolated, purified, and characterized by NMR and mass spectrometry. The antitrypanosomal agent in the CHCl3 extract of T. longipes leaves is the pentacyclic triterpenoid bauerenol acetate. A metabolite profiling assay suggest that the triterpenoid influences cholesterol metabolism. The molecular target(s) of bauerenol and its acetate, like many other antiparasitic pentacyclic triterpenoids is/are unknown, but they present privileged structural scaffolds that can be explored for structure-based activity optimization studies using phenotypic assays.
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Sterol targeting drugs reveal life cycle stage-specific differences in trypanosome lipid rafts. Sci Rep 2017; 7:9105. [PMID: 28831063 PMCID: PMC5567337 DOI: 10.1038/s41598-017-08770-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 06/28/2017] [Indexed: 12/16/2022] Open
Abstract
Cilia play important roles in cell signaling, facilitated by the unique lipid environment of a ciliary membrane containing high concentrations of sterol-rich lipid rafts. The African trypanosome Trypanosoma brucei is a single-celled eukaryote with a single cilium/flagellum. We tested whether flagellar sterol enrichment results from selective flagellar partitioning of specific sterol species or from general enrichment of all sterols. While all sterols are enriched in the flagellum, cholesterol is especially enriched. T. brucei cycles between its mammalian host (bloodstream cell), in which it scavenges cholesterol, and its tsetse fly host (procyclic cell), in which it both scavenges cholesterol and synthesizes ergosterol. We wondered whether the insect and mammalian life cycle stages possess chemically different lipid rafts due to different sterol utilization. Treatment of bloodstream parasites with cholesterol-specific methyl-β-cyclodextrin disrupts both membrane liquid order and localization of a raft-associated ciliary membrane calcium sensor. Treatment with ergosterol-specific amphotericin B does not. The opposite results were observed with ergosterol-rich procyclic cells. Further, these agents have opposite effects on flagellar sterol enrichment and cell metabolism in the two life cycle stages. These findings illuminate differences in the lipid rafts of an organism employing life cycle-specific sterols and have implications for treatment.
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Cullen DR, Pengon J, Rattanajak R, Chaplin J, Kamchonwongpaisan S, Mocerino M. Scoping Studies into the Structure-Activity Relationship (SAR) of Phenylephrine-Derived Analogues as Inhibitors ofTrypanosoma brucei rhodesiense. ChemistrySelect 2016. [DOI: 10.1002/slct.201601059] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Danica R. Cullen
- Department of Chemistry; Curtin University; GPO Box U1987 Perth WA 6845 Australia
| | - Jutharat Pengon
- BIOTEC Medical Molecular Biology Research Unit; National Science and Technology Development Agency; 113 Thailand Science Park, Phahonyothin Road Khlong Nueng, Khlong Luang, Pathum Thani 12120 Thailand
| | - Roonglawan Rattanajak
- BIOTEC Medical Molecular Biology Research Unit; National Science and Technology Development Agency; 113 Thailand Science Park, Phahonyothin Road Khlong Nueng, Khlong Luang, Pathum Thani 12120 Thailand
| | - Jason Chaplin
- Epichem Pty Ltd; Suite 5, 3 Brodie-Hall Drive Bentley WA 6102 Australia
| | - Sumalee Kamchonwongpaisan
- BIOTEC Medical Molecular Biology Research Unit; National Science and Technology Development Agency; 113 Thailand Science Park, Phahonyothin Road Khlong Nueng, Khlong Luang, Pathum Thani 12120 Thailand
| | - Mauro Mocerino
- Department of Chemistry; Curtin University; GPO Box U1987 Perth WA 6845 Australia
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Isolation and identification of antitrypanosomal and antimycobacterial active steroids from the sponge Haliclona simulans. Mar Drugs 2014; 12:2937-52. [PMID: 24862183 PMCID: PMC4052325 DOI: 10.3390/md12052937] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 04/25/2014] [Accepted: 04/28/2014] [Indexed: 11/27/2022] Open
Abstract
The marine sponge Haliclona simulans collected from the Irish Sea yielded two new steroids: 24-vinyl-cholest-9-ene-3β,24-diol and 20-methyl-pregn-6-en-3β-ol,5α,8α-epidioxy, along with the widely distributed 24-methylenecholesterol. One of the steroids possesses an unusually short hydrocarbon side chain. The structures were elucidated using nuclear magnetic resonance spectroscopy and confirmed using electron impact- and high resolution electrospray-mass spectrometry. All three steroids possess antitrypanosomal and anti-mycobacterial activity. All the steroids were found to possess low cytotoxicity against Hs27 which was above their detected antitrypanosomal potent concentrations.
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Fügi MA, Gunasekera K, Ochsenreiter T, Guan X, Wenk MR, Mäser P. Genome profiling of sterol synthesis shows convergent evolution in parasites and guides chemotherapeutic attack. J Lipid Res 2014; 55:929-38. [PMID: 24627128 DOI: 10.1194/jlr.m048017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Sterols are an essential class of lipids in eukaryotes, where they serve as structural components of membranes and play important roles as signaling molecules. Sterols are also of high pharmacological significance: cholesterol-lowering drugs are blockbusters in human health, and inhibitors of ergosterol biosynthesis are widely used as antifungals. Inhibitors of ergosterol synthesis are also being developed for Chagas's disease, caused by Trypanosoma cruzi. Here we develop an in silico pipeline to globally evaluate sterol metabolism and perform comparative genomics. We generate a library of hidden Markov model-based profiles for 42 sterol biosynthetic enzymes, which allows expressing the genomic makeup of a given species as a numerical vector. Hierarchical clustering of these vectors functionally groups eukaryote proteomes and reveals convergent evolution, in particular metabolic reduction in obligate endoparasites. We experimentally explore sterol metabolism by testing a set of sterol biosynthesis inhibitors against trypanosomatids, Plasmodium falciparum, Giardia, and mammalian cells, and by quantifying the expression levels of sterol biosynthetic genes during the different life stages of T. cruzi and Trypanosoma brucei. The phenotypic data correlate with genomic makeup for simvastatin, which showed activity against trypanosomatids. Other findings, such as the activity of terbinafine against Giardia, are not in agreement with the genotypic profile.
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Affiliation(s)
- Matthias A Fügi
- Swiss Tropical and Public Health Institute, Basel, Switzerland
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Upadhayaya RS, Dixit SS, Földesi A, Chattopadhyaya J. New antiprotozoal agents: Their synthesis and biological evaluations. Bioorg Med Chem Lett 2013; 23:2750-8. [DOI: 10.1016/j.bmcl.2013.02.054] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2013] [Revised: 02/08/2013] [Accepted: 02/12/2013] [Indexed: 11/26/2022]
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Rateb ME, Hallyburton I, Houssen WE, Bull AT, Goodfellow M, Santhanam R, Jaspars M, Ebel R. Induction of diverse secondary metabolites in Aspergillus fumigatus by microbial co-culture. RSC Adv 2013. [DOI: 10.1039/c3ra42378f] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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Design, synthesis and in vitro antimicrobial activity of novel phenylbenzamido-aminothiazole-based azasterol mimics. Med Chem Res 2012. [DOI: 10.1007/s00044-012-0314-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Endogenous sterol biosynthesis is important for mitochondrial function and cell morphology in procyclic forms of Trypanosoma brucei. Int J Parasitol 2012; 42:975-89. [PMID: 22964455 DOI: 10.1016/j.ijpara.2012.07.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 07/19/2012] [Accepted: 07/22/2012] [Indexed: 11/22/2022]
Abstract
Sterol biosynthesis inhibitors are promising entities for the treatment of trypanosomal diseases. Insect forms of Trypanosoma brucei, the causative agent of sleeping sickness, synthesize ergosterol and other 24-alkylated sterols, yet also incorporate cholesterol from the medium. While sterol function has been investigated by pharmacological manipulation of sterol biosynthesis, molecular mechanisms by which endogenous sterols influence cellular processes remain largely unknown in trypanosomes. Here we analyse by RNA interference, the effects of a perturbation of three specific steps of endogenous sterol biosynthesis in order to dissect the role of specific intermediates in proliferation, mitochondrial function and cellular morphology in procyclic cells. A decrease in the levels of squalene synthase and squalene epoxidase resulted in a depletion of cellular sterol intermediates and end products, impaired cell growth and led to aberrant morphologies, DNA fragmentation and a profound modification of mitochondrial structure and function. In contrast, cells deficient in sterol methyl transferase, the enzyme involved in 24-alkylation, exhibited a normal growth phenotype in spite of a complete abolition of the synthesis and content of 24-alkyl sterols. Thus, the data provided indicates that while the depletion of squalene and post-squalene endogenous sterol metabolites results in profound cellular defects, bulk 24-alkyl sterols are not strictly required to support growth in insect forms of T. brucei in vitro.
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Novel sterol metabolic network of Trypanosoma brucei procyclic and bloodstream forms. Biochem J 2012; 443:267-77. [PMID: 22176028 DOI: 10.1042/bj20111849] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Trypanosoma brucei is the protozoan parasite that causes African trypanosomiasis, a neglected disease of people and animals. Co-metabolite analysis, labelling studies using [methyl-2H3]-methionine and substrate/product specificities of the cloned 24-SMT (sterol C24-methyltransferase) and 14-SDM (sterol C14demethylase) from T. brucei afforded an uncommon sterol metabolic network that proceeds from lanosterol and 31-norlanosterol to ETO [ergosta-5,7,25(27)-trien-3β-ol], 24-DTO [dimethyl ergosta-5,7,25(27)-trienol] and ergosterol [ergosta-5,7,22(23)-trienol]. To assess the possible carbon sources of ergosterol biosynthesis, specifically 13C-labelled specimens of lanosterol, acetate, leucine and glucose were administered to T. brucei and the 13C distributions found were in accord with the operation of the acetate-mevalonate pathway, with leucine as an alternative precursor, to ergostenols in either the insect or bloodstream form. In searching for metabolic signatures of procyclic cells, we observed that the 13C-labelling treatments induce fluctuations between the acetyl-CoA (mitochondrial) and sterol (cytosolic) synthetic pathways detected by the progressive increase in 13C-ergosterol production (control<[2-(13)C]leucine<[2-(13)C]acetate<[1-(13)C]glucose) and corresponding depletion of cholesta-5,7,24-trienol. We conclude that anabolic fluxes originating in mitochondrial metabolism constitute a flexible part of sterol synthesis that is further fluctuated in the cytosol, yielding distinct sterol profiles in relation to cell demands on growth.
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Lepesheva GI, Villalta F, Waterman MR. Targeting Trypanosoma cruzi sterol 14α-demethylase (CYP51). ADVANCES IN PARASITOLOGY 2011; 75:65-87. [PMID: 21820552 DOI: 10.1016/b978-0-12-385863-4.00004-6] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
There are at least two obvious features that must be considered upon targeting specific metabolic pathways/enzymes for drug development: the pathway must be essential and the enzyme must allow the design of pharmacologically useful inhibitors. Here, we describe Trypanosoma cruzi sterol 14α-demethylase as a promising target for anti-Chagasic chemotherapy. The use of anti-fungal azoles, which block sterol biosynthesis and therefore membrane formation in fungi, against the protozoan parasite has turned out to be highly successful: a broad spectrum anti-fungal drug, the triazole compound posaconazole, is now entering phase II clinical trials for treatment of Chagas disease. This review summarizes comparative information on anti-fungal azoles and novel inhibitory scaffolds selective for Trypanosomatidae sterol 14α-demethylase through the lens of recent structure/functional characterization of the target enzyme. We believe our studies open wide opportunities for rational design of novel, pathogen-specific and therefore more potent and efficient anti-trypanosomal drugs.
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Affiliation(s)
- Galina I Lepesheva
- Department of Biochemistry School of Medicine, Vanderbilt University, Nashville, Tennessee, USA
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Vanichtanankul J, Taweechai S, Yuvaniyama J, Vilaivan T, Chitnumsub P, Kamchonwongpaisan S, Yuthavong Y. Trypanosomal dihydrofolate reductase reveals natural antifolate resistance. ACS Chem Biol 2011; 6:905-11. [PMID: 21650210 DOI: 10.1021/cb200124r] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Dihydrofolate reductase (DHFR) is a potential drug target for Trypanosoma brucei, a human parasite, which is the causative agent for African sleeping sickness. No drug is available against this target, since none of the classical antifolates such as pyrimethamine (PYR), cycloguanil, or trimethoprim are effective as selective inhibitors of T. brucei DHFR (TbDHFR). In order to design effective drugs that target TbDHFR, co-crystal structures with bound antifolates were studied. On comparison with malarial Plasmodium falciparum DHFR (PfDHFR), the co-crystal structures of wild-type TbDHFR reveal greater structural similarities to a mutant PfDHFR causing antifolate resistance than the wild-type enzyme. TbDHFR imposes steric hindrance for rigid inhibitors like PYR around Thr86, which is equivalent to Ser108Asn of the malarial enzymes. In addition, a missing residue on TbDHFR active-site loop together with the presence of Ile51 widens its active site even further than the structural effect of Asn51Ile, which is observed in PfDHFR structures. The structural similarities are paralleled by the similarly poor affinities of the trypanosomal enzyme for rigid inhibitors. Mutations of TbDHFR at Thr86 resulted in 10-fold enhancement or 7-fold reduction in the rigid inhibitors affinities for Thr86Ser or Thr86Asn, respectively. The co-crystal structure of TbDHFR with a flexible antifolate WR99210 suggests that its greater affinity result from its ability to avoid such Thr86 clash and occupy the widened binding space similarly to what is observed in the PfDHFR structures. Natural resistance to antifolates of TbDHFR can therefore be explained, and potential antifolate chemotherapy of trypanosomiasis should be possible taking this into account.
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Affiliation(s)
- Jarunee Vanichtanankul
- National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, 113 Thailand Science Park, Paholyothin Road, Klong Luang, Pathumthani 12120, Thailand
- Department of Biochemistry and Center for Excellence in Protein Structure and Function, Faculty of Science, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand
| | - Supannee Taweechai
- National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, 113 Thailand Science Park, Paholyothin Road, Klong Luang, Pathumthani 12120, Thailand
| | - Jirundon Yuvaniyama
- Department of Biochemistry and Center for Excellence in Protein Structure and Function, Faculty of Science, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand
| | - Tirayut Vilaivan
- Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Penchit Chitnumsub
- National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, 113 Thailand Science Park, Paholyothin Road, Klong Luang, Pathumthani 12120, Thailand
| | - Sumalee Kamchonwongpaisan
- National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, 113 Thailand Science Park, Paholyothin Road, Klong Luang, Pathumthani 12120, Thailand
| | - Yongyuth Yuthavong
- National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, 113 Thailand Science Park, Paholyothin Road, Klong Luang, Pathumthani 12120, Thailand
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Wangchuk P, Keller PA, Pyne SG, Taweechotipatr M, Tonsomboon A, Rattanajak R, Kamchonwongpaisan S. Evaluation of an ethnopharmacologically selected Bhutanese medicinal plants for their major classes of phytochemicals and biological activities. JOURNAL OF ETHNOPHARMACOLOGY 2011; 137:730-42. [PMID: 21741462 DOI: 10.1016/j.jep.2011.06.032] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Accepted: 06/20/2011] [Indexed: 05/25/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE As many as 229 medicinal plants have been currently used in the Bhutanese Traditional Medicine (BTM) as a chief ingredient of polyherbal formulations and these plants have been individually indicated for treating various types of infections including malaria, tumor, and microbial. We have focused our study only on seven species of these plants. AIM OF THE STUDY We aim to evaluate the antiplasmodial, antimicrobial, anti-Trypanosoma brucei rhodesiense and cytotoxicity activities of the seven medicinal plants of Bhutan selected using an ethno-directed bio-rational approach. This study creates a scientific basis for their use in the BTM and gives foundation for further phytochemical and biological evaluations which can result in the discovery of new drug lead compounds. MATERIALS AND METHODS A three stage process was conducted which consisted of: (1) an assessment of a pharmacopoeia and a formulary book of the BTM for their mode of plant uses; (2) selecting 25 anti-infective medicinal plants based on the five established criteria, collecting them, and screening for their major classes of phytochemicals using appropriate test protocols; and (3) finally analyzing the crude extracts of the seven medicinal plants, using the standard test protocols, for their antiplasmodial, antimicrobial, anti-Trypanosoma brucei rhodesiense and cytotoxicity activities as directed by the ethnopharmacological uses of each plant. RESULTS Out of 25 medicinal plants screened for their major classes of phytochemicals, the majority contained tannins, alkaloids and flavonoids. Out of the seven plant species investigated for their biological activities, all seven of them exhibited mild antimicrobial properties, five plants gave significant in vitro antiplasmodial activities, two plants gave moderate anti-Trypanosoma brucei rhodesiense activity, and one plant showed mild cytotoxicity. Meconopsis simplicifolia showed the highest antiplasmodial activity with IC(50) values of 0.40 μg/ml against TM4/8.2 strain (a wild type chloroquine and antifolate sensitive strain) and 6.39 μg/ml against K1CB1 (multidrug resistant strain) strain. Significantly the extracts from this plant did not show any cytotoxicity. CONCLUSIONS These findings provide the scientific basis for the use of seven medicinal plants in the BTM for the treatment of malaria, microbial infections, infectious fevers, and the Trypanosoma brucei rhodesiense infection. The results also form a good preliminary basis for the prioritization of candidate plant species for further in-depth phytochemical and pharmacological investigations toward our quest to unearth lead antiparasitic, anticancer and antimicrobial compounds.
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Affiliation(s)
- Phurpa Wangchuk
- School of Chemistry, University of Wollongong, Wollongong, NSW 2522, Australia.
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Ganapathy K, Kanagasabai R, Nguyen TTM, Nes WD. Purification, characterization and inhibition of sterol C24-methyltransferase from Candida albicans. Arch Biochem Biophys 2011; 505:194-201. [DOI: 10.1016/j.abb.2010.10.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Revised: 10/05/2010] [Accepted: 10/07/2010] [Indexed: 10/19/2022]
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Martins-Duarte ES, Lemgruber L, Lorente SO, Gros L, Magaraci F, Gilbert IH, de Souza W, Vommaro RC. Evaluation of three novel azasterols against Toxoplasma gondii. Vet Parasitol 2010; 177:157-61. [PMID: 21176865 DOI: 10.1016/j.vetpar.2010.11.034] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2010] [Revised: 11/19/2010] [Accepted: 11/23/2010] [Indexed: 10/18/2022]
Abstract
Previous studies from our group have demonstrated the high susceptibility of Toxoplasma gondii tachyzoites to the sterol analogues 22,26-azasterol and 24,25-(R,S)-epiminolanosterol. In this work we present data on testing in vitro three novel azasterols as potential agents for the treatment of toxoplasmosis. The three compounds inhibited parasite growth at micromolar concentrations, in a dose-dependent manner. Electron microscopy analysis of intracellular tachyzoites after treatment with the most effective compound showed drastic mitochondrion swelling associated with the appearance of an electron-lucent matrix and disrupted cristae. Parasite lysis also took place. The appearance of electron dense cytoplasmic structures similar to amylopectin granules distributed throughout the parasite suggests that azasterols might be inducing differentiation of those tachyzoites which were not lysed to the bradyzoite stage.
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Affiliation(s)
- Erica S Martins-Duarte
- Laboratório de Ultraestrutura Celular Herth, Meyer, Instituto de Biofísica Carlos Chagas Filho, UFRJ, CCS, Bloco G, Av. Carlo, Chagas Filho, Cidade Universitária, Ilha do Fundão, 21941-902, Rio de Janeiro, RJ, Brazil
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Abstract
The protozoan parasitesTrypanosoma bruceiandTrypanosoma cruziare the causative agents of African trypanosomiasis and Chagas disease, respectively. These are debilitating infections that exert a considerable health burden on some of the poorest people on the planet. Treatment of trypanosome infections is dependent on a small number of drugs that have limited efficacy and can cause severe side effects. Here, we review the properties of these drugs and describe new findings on their modes of action and the mechanisms by which resistance can arise. We further outline how a greater understanding of parasite biology is being exploited in the search for novel chemotherapeutic agents. This effort is being facilitated by new research networks that involve academic and biotechnology/pharmaceutical organisations, supported by public–private partnerships, and are bringing a new dynamism and purpose to the search for trypanocidal agents.
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Sterol Biosynthesis Pathway as Target for Anti-trypanosomatid Drugs. Interdiscip Perspect Infect Dis 2009; 2009:642502. [PMID: 19680554 PMCID: PMC2721973 DOI: 10.1155/2009/642502] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2009] [Accepted: 04/27/2009] [Indexed: 12/03/2022] Open
Abstract
Sterols are constituents of the cellular membranes that are essential for their normal structure and function. In mammalian cells, cholesterol is the main sterol found in the various membranes. However, other sterols predominate in eukaryotic microorganisms such as fungi and protozoa. It is now well established that an important metabolic pathway in fungi and in members of the Trypanosomatidae family is one that produces a special class of sterols, including ergosterol, and other 24-methyl sterols, which are required for parasitic growth and viability, but are absent from mammalian host cells. Currently, there are several drugs that interfere with sterol biosynthesis (SB) that are in use to treat diseases such as high cholesterol in humans and fungal infections. In this review, we analyze the effects of drugs such as (a) statins, which act on the mevalonate pathway by inhibiting HMG-CoA reductase, (b) bisphosphonates, which interfere with the isoprenoid pathway in the step catalyzed by farnesyl diphosphate synthase, (c) zaragozic acids and quinuclidines, inhibitors of squalene synthase (SQS), which catalyzes the first committed step in sterol biosynthesis, (d) allylamines, inhibitors of squalene epoxidase, (e) azoles, which inhibit C14α-demethylase, and (f) azasterols, which inhibit Δ24(25)-sterol methyltransferase (SMT). Inhibition of this last step appears to have high selectivity for fungi and trypanosomatids, since this enzyme is not found in mammalian cells. We review here the IC50 values of these various inhibitors, their effects on the growth of trypanosomatids (both in axenic cultures and in cell cultures), and their effects on protozoan structural organization (as evaluted by light and electron microscopy) and lipid composition. The results show that the mitochondrial membrane as well as the membrane lining the protozoan cell body and flagellum are the main targets. Probably as a consequence of these primary effects, other important changes take place in the organization of the kinetoplast DNA network and on the protozoan cell cycle. In addition, apoptosis-like and autophagic processes induced by several of the inhibitors tested led to parasite death.
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Gigante F, Kaiser M, Brun R, Gilbert IH. SAR studies on azasterols as potential anti-trypanosomal and anti-leishmanial agents. Bioorg Med Chem 2009; 17:5950-61. [PMID: 19620005 DOI: 10.1016/j.bmc.2009.06.062] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Revised: 06/20/2009] [Accepted: 06/28/2009] [Indexed: 11/29/2022]
Abstract
There is an urgent need for the development of new drugs for the treatment of neglected tropical diseases such as human African trypanosomiasis, Chagas disease and leishmaniasis. Azasterols, have been shown to have activity against the parasites which cause these diseases. In this paper we report synthesis of new azasterols and subsequent analysis of the SAR. The chemistry focused on variations in the ester at the 3beta-position of the sterol and the position of the nitrogen in the side chain. The data allowed us to derive preliminary pharmacophore models for the activity of the azasterols against the parasites which cause these diseases.
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Ishida K, Rodrigues JCF, Ribeiro MD, Vila TVM, de Souza W, Urbina JA, Nakamura CV, Rozental S. Growth inhibition and ultrastructural alterations induced by Delta24(25)-sterol methyltransferase inhibitors in Candida spp. isolates, including non-albicans organisms. BMC Microbiol 2009; 9:74. [PMID: 19379501 PMCID: PMC2679025 DOI: 10.1186/1471-2180-9-74] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2008] [Accepted: 04/20/2009] [Indexed: 11/10/2022] Open
Abstract
Background Although Candida species are commensal microorganisms, they can cause many invasive fungal infections. In addition, antifungal resistance can contribute to failure of treatment. The purpose of this study was to evaluate the antifungal activity of inhibitors of Δ24(25)-sterol methyltransferase (24-SMTI), 20-piperidin-2-yl-5α-pregnan-3β-20(R)-diol (AZA), and 24(R,S),25-epiminolanosterol (EIL), against clinical isolates of Candida spp., analysing the ultrastructural changes. Results AZA and EIL were found to be potent growth inhibitors of Candida spp. isolates. The median MIC50 was 0.5 μg.ml-1 for AZA and 2 μg.ml-1 for EIL, and the MIC90 was 2 μg.ml-1 for both compounds. All strains used in this study were susceptible to amphotericin B; however, some isolates were fluconazole- and itraconazole-resistant. Most of the azole-resistant isolates were Candida non-albicans (CNA) species, but several of them, such as C. guilliermondii, C. zeylanoides, and C. lipolytica, were susceptible to 24-SMTI, indicating a lack of cross-resistance. Reference strain C. krusei (ATCC 6258, FLC-resistant) was consistently susceptible to AZA, although not to EIL. The fungicidal activity of 24-SMTI was particularly high against CNA isolates. Treatment with sub-inhibitory concentrations of AZA and EIL induced several ultrastructural alterations, including changes in the cell-wall shape and thickness, a pronounced disconnection between the cell wall and cytoplasm with an electron-lucent zone between them, mitochondrial swelling, and the presence of electron-dense vacuoles. Fluorescence microscopy analyses indicated an accumulation of lipid bodies and alterations in the cell cycle of the yeasts. The selectivity of 24-SMTI for fungal cells versus mammalian cells was assessed by the sulforhodamine B viability assay. Conclusion Taken together, these results suggest that inhibition of 24-SMT may be a novel approach to control Candida spp. infections, including those caused by azole-resistant strains.
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Affiliation(s)
- Kelly Ishida
- Laboratório de Biologia Celular de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
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Jiménez-Jiménez C, Carrero-Lérida J, Sealey-Cardona M, Ruiz Pérez LM, Urbina JA, González Pacanowska D. Delta24(25)-sterol methenyltransferase: intracellular localization and azasterol sensitivity in Leishmania major promastigotes overexpressing the enzyme. Mol Biochem Parasitol 2008; 160:52-9. [PMID: 18485498 DOI: 10.1016/j.molbiopara.2008.03.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2007] [Revised: 03/19/2008] [Accepted: 03/31/2008] [Indexed: 11/25/2022]
Abstract
Trypanosomatids contain predominantly ergostane-based sterols, which differ from cholesterol, the main sterol in mammalian cells, in the presence of a methyl group in the 24 position. The methylation is initiated by S-adenosyl-L-methionine:Delta(24 (25))-sterol methenyltransferase, an enzyme present in protozoa, but absent in mammals. The importance of this enzyme is underscored by its potential as a drug target in the treatment of the leishmaniases. Here, we report studies concerning the intracellular distribution of sterol methenyltransferase in Leishmania major promastigotes and overexpressing cells using a specific antibody raised against highly purified recombinant protein. It was found by immunofluorescence and electron microscopy studies that in L. major wild-type cells sterol methenyltransferase was primarily associated to the endoplasmic reticulum. In addition to this location, the protein was incorporated into translucent vesicles presumably of the endocytic pathway. We also found in this study that cells overproducing the enzyme do not have increased resistance to the sterol methenyltransferase inhibitor 22, 26 azasterol.
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Affiliation(s)
- Carmen Jiménez-Jiménez
- Instituto de Parasitología y Biomedicina López-Neyra, Consejo Superior de Investigaciones Científicas, Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, s/n 18100 Armilla, Granada, Spain
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Cammerer SB, Jimenez C, Jones S, Gros L, Lorente SO, Rodrigues C, Rodrigues JCF, Caldera A, Ruiz Perez LM, da Souza W, Kaiser M, Brun R, Urbina JA, Gonzalez Pacanowska D, Gilbert IH. Quinuclidine derivatives as potential antiparasitics. Antimicrob Agents Chemother 2007; 51:4049-61. [PMID: 17709461 PMCID: PMC2151445 DOI: 10.1128/aac.00205-07] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
There is an urgent need for the development of new drugs for the treatment of tropical parasitic diseases such as Chagas' disease and leishmaniasis. One potential drug target in the organisms that cause these diseases is sterol biosynthesis. This paper describes the design and synthesis of quinuclidine derivatives as potential inhibitors of a key enzyme in sterol biosynthesis, squalene synthase (SQS). A number of compounds that were inhibitors of the recombinant Leishmania major SQS at submicromolar concentrations were discovered. Some of these compounds were also selective for the parasite enzyme rather than the homologous human enzyme. The compounds inhibited the growth of and sterol biosynthesis in Leishmania parasites. In addition, we identified other quinuclidine derivatives that inhibit the growth of Trypanosoma brucei (the causative organism of human African trypanosomiasis) and Plasmodium falciparum (a causative agent of malaria), but through an unknown mode(s) of action.
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Gros L, Lorente SO, Jimenez CJ, Yardley V, Rattray L, Wharton H, Little S, Croft SL, Ruiz-Perez LM, Gonzalez-Pacanowska D, Gilbert IH. Evaluation of Azasterols as Anti-Parasitics. J Med Chem 2006; 49:6094-103. [PMID: 17004723 DOI: 10.1021/jm060290f] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this article, the design and synthesis of some novel azasterols is described, followed by their evaluation against Trypanosoma brucei rhodesiense, T. cruzi, Leishmania donovani, and Plasmodium falciparum, the causative agents of human African trypanosomiasis, Chagas disease, leishmaniasis, and malaria, respectively. Some of the compounds showed anti-parasitic activity. In particular, a number of compounds appeared to very potently inhibit the growth of the blood stream form T. b. rhodesiense, with one compound giving an IC50 value of 12 nM. Clear structure activity relationships could be discerned. These compounds represent important leads for further optimization. Azasterols have previously been shown to inhibit sterol biosynthesis in T. cruzi and L. donovani by the inhibition of the enzyme sterol 24-methyltransferase. However, in this case, none of the compounds showed inhibition of the enzyme. Therefore, these compounds have an unknown mode of action.
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Affiliation(s)
- Ludovic Gros
- Welsh School of Pharmacy, Cardiff University, Redwood Building, King Edward VII Avenue, Cardiff CF10 3XF, UK
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